Use of communication systems through which to communicate data between two, or more, locations is an endemic part of modern society. Communication stations are positioned at the separate locations and operate to effectuate the communication of the data.
In a minimal implementation, the communication system is formed of a first communication station, forming a sending station, and a second communication station, forming a receiving station. A communication channel interconnects the communication stations. Data that is to be communicated by the first communication station to the second communication station is converted, if necessary, into a form to permit its communication upon the communication channel. And, the second communication station operates to detect the data communicated thereto by the first communication station and to recover the informational content thereof.
In a radio communication system, the communication channel that interconnects the sending and receiving stations is formed of a radio channel, defined upon a radio link, formed upon the electromagnetic spectrum. Other, conventional communication systems generally require a fixed, wireline connection extending between the communication stations upon which to define communication channels.
As a radio link, rather than a wireline connection, is utilized upon which to define the communication channels, the need otherwise to utilize wireline connections upon which to define the communication channels is obviated. As a result, installation of the infrastructure of the radio communication system is generally less costly than the corresponding costs that would be required to construct a conventional, wireline communication system. And, mobility of the communication station can be provided, thereby to permit a radio communication system to form a mobile radio communication system.
A cellular communication system is an exemplary type of radio communication system. Cellular communication systems have been widely implemented and have achieved wide levels of usage. A cellular communication system provides for radio communications with mobile stations. The mobile stations permit telephonic communication to be effectuated therethrough. And, mobile stations are generally of sizes to permit their carriage by users of the mobile stations.
A cellular communication system includes a network part that is installed throughout a geographical area and with which the mobile stations communicate by way of radio channels defined upon radio links allocated to the communication system.
Base transceiver stations, forming portions of the network part of the communication system, are installed at spaced-apart locations throughout the geographical area that is to be encompassed by the communication system. Each of the base transceiver stations defines a cell, formed of a portion of the geographical area. And, the term cellular is derived from the cells defined by the base transceiver stations.
When a mobile station is within the cell defined by a base transceiver station, communications are generally effectuable with the base transceiver station that defines the cell. As a mobile station travels between the cells defined by different ones of the base transceiver stations, communication handoffs are effectuated to permit continued communications by, and with, the mobile station. Through appropriate positioning of the base transceiver stations, the mobile station, wherever positioned within the geographical area encompassed by the cellular communication system, shall be within close proximity of at least one base transceiver station. Therefore, only relatively low-powered signals need to be generated to effectuate communications between a mobile station and a base transceiver station. Hand-offs of communications between successive base transceiver stations, as the mobile station moves between cells, permit the continued communications without necessitating increase in the power levels at which the communication signals are transmitted. And, the low-power nature of the signals that are generated permit the same radio channels to be reused at different locations of the cellular communication system. Efficient utilization of the frequency-spectrum allocation to the cellular communication system is thereby possible.
Cellular, as well as various other, communication systems are constructed to be operable pursuant to an appropriate operating specification. Successive generations of operating specifications have been promulgated. And, corresponding generations of cellular communication networks have been installed throughout wide areas to permit telephonic communications therethrough. So-called first-generation and second-generation cellular communication networks have been widely implemented and have achieved significant levels of usage. And, installation of so-called third-generation and successor-generation systems have been proposed.
An exemplary operating specification, referred to as the CDMA 2000 specification, sets forth the operating parameters of an exemplary, third-generation communication system. The CDMA 2000 operating specification, as well as other third-generation operating specifications, provide for packet-based data communication services. The CDMA 2000 operating specification provides for high data rate communication services to be effectuated therethrough.
In a CDMA 2000 communication system, allocation of channel capacity is a mandatory aspect that must be performed to permit multiple numbers of users to access the communication system and communicate therethrough. And, due to the shared nature of the radio spectrum allocated to a communication system that utilizes code-division techniques, the allocation of channels is of particular significance. Radio channel allocation of shared resources in a multiple-user system effects the usage efficiency of the radio spectrum allocated to the communication system as well as communication performance of the communication system.
The CDMA 2000 operating specification that provides for 1xc3x97EV-DV data communications defines a high-speed forward channel upon which packet data communication services are effectuated. Multiple numbers of users with whom the high-speed data services are effectuated share the high-speed forward channel. And, the numbers of users that are permitted to utilize the forward channel varies, e.g., up to fifty users, depending upon factors including the radio conditions and dynamic traffic needs.
Two general schemes are utilized in the allocation and management of the shared channels for multiple users in the 1xc3x97EV-DV system. Namely, a time division multiplexing (TDM) scheme is set forth, and a time/code-division multiplexing (TDM/CDM) scheme is set forth. Various, and sometimes competing, framework proposals have been set forth, utilizing the different multiplexing schemes. An L3NQS scheme utilizing TDM and a 1XTREME scheme utilizing TDM/CDM have both been set forth. A TDM/CDM multiplexing scheme permits the efficiency of dealing with a mixture of different types of applications utilizing high data rate communications and low data rate communications to be increased.
TDM/CDM control schemes have been proposed in 1xc3x97EV-DV, e.g., 1XTREME. One such existing control scheme is used in the official 1XTREME framework. And, another existing scheme has been proposed as a harmonization proposal harmonizing 1XTREME and L3NQS schemes.
The 1XTREME scheme utilizes a fixed frame length channel structure. The control scheme enables multiple users to access shared forward channels simultaneously. Each user is assigned with a dedicated pointer channel that provides a pointer, pointing to a corresponding forward shared control channel. Over one forward shared control channel, information, e.g., Walsh code assignment, etc., related to one, or more, forward shared channels is carried. This scheme exhibits drawbacks, however. First, one dedicated pointer is required for each mobile station. This requirement implies that the overhead of Walsh code space and power allocation for multiple dedicated pointer channels is necessitated. And, the 1XTREME control scheme also fails to take into account the possibility that a frame can be of a variable frame length.
And, in the 1xc3x97EV-DV harmonized proposal, each mobile station monitors multiple forward shared channels to determine the forward shared channel assignments. If assigned, information carried on the forward shared control channels provides sufficient information for the mobile station to receive traffic data upon the appropriate forward shared traffic channel. In such a scheme, all of the mobile stations monitor all of the shared control channels simultaneously. And, code division modulation can be realized. The need, however, to monitor the multiple shared control channels, both while the mobile stations are in the control hold state as well as also when the mobile stations are in the active state, is energy-consumptive. And, battery depletion of mobile stations operable in such a scheme poses a problem.
Accordingly, an improved manner by which to allocate and control the shared channel in a packet radio, or other, communication system is required.
It is in light of this background information related to communications in a radio communication system that utilizes shared channels that the significant improvements of the present invention have evolved.
The present invention, accordingly, advantageously provides apparatus, and an associated method, by which to facilitate efficient radio resource utilization in a radio communication system that utilizes shared channels.
Through operation of an embodiment of the present invention, a manner is provided by which to allocate, control, and manage the shared channel through the generation of CDM (code division multiplexing) assignment information. Through such channel allocation, control, and management, efficient usage of the radio resources allocated to the radio communication system is permitted, thereby improving the communication capacity of the system and improving system efficiency.
In one aspect of the present invention, an allocation scheme is provided in which a single common, shared control channel is utilized for all of the mobile stations. Each mobile station, whether in a packet-data active state or a packet-data control hold state, monitors the shared, common control channel for CDM channel allocation information. Multiple sets of CDM assignment information is sent on this shared, common control channel to be provided to the mobile stations. And, a single spreading factor is utilized.
Because the mobile stations need only monitor a single shared, common control channel, the power required of the mobile station to monitor for control information is minimized.
In another aspect of the present invention, assignment of a single, shared common control channel is again assigned and utilized by all of the mobile stations to obtain CDM channel allocation information. The frame length of the frames of the CDM channel allocation information into which such channel allocation information is formatted need not be of a fixed frame length. Rather, the frame length is permitted to be of a variable frame length. Increased system flexibility is permitted through the capability of formatting the assignment information into a frame of a variable frame length. A single spreading factor is also, again, utilized.
In another aspect of the present invention, a plurality of two, or more, common, shared control channels are utilized and CDM assignment information is communicated thereon. Each mobile station is assigned to a selected, shared control channel, thereby to permit the mobile station to monitor a single shared, control channel, i.e., the shared, control channel that is assigned to the particular mobile station.
In another aspect of the present invention, the multiplicity of common, shared control channels is again utilized. And, further, the CDM assignment information is formatted into frames of variable frame lengths. By forming the CDM assignment information into frames of selectable frame lengths, the flexibility of the control mechanism provided to the communication system is improved.
In the exemplary implementation, one of the aforementioned control schemes is implemented in a CDMA 2000 communication scheme that provides for high data-rate communications. Mobile stations register with the communication system pursuant to registration procedures. Responsive to registration of a mobile station to the communication system, CDM control information is sent to the mobile station. The mobile station monitors a common, shared control channel to which the mobile station is assigned to receive CDM assignment information thereon. Because only a single channel is monitored by the mobile station, reduced energy consumption is required of the mobile station pursuant to monitoring of control information, required pursuant to operation of the mobile station in the communication system. The effectuation of high-data-rate communication with the mobile station is thereby facilitated.
In these and other aspects, therefore, apparatus, and an associated method, is provided for a radio communication system. During operation of the radio communication system, code division multiplexed data is communicated between a network part and a plurality of communication stations including a first station and at least a second station. Communication of the data upon at least a first shared channel is facilitated. A CDM (code division multiplexing) assignment information generator generates CDM assignment information. The CDM assignment information forms a first multiple assignment information set and at least a second multiple assignment information set for communications with each of the first station and the at least the second station.
A more complete appreciation of the present invention and the scope thereof can be obtained from the accompanying drawings that are briefly summarized below, the following detailed description of the presently preferred embodiments of the invention, and the appended claims.